CRISPR Can Tag RNA

Modifications to the DNA-slicing program allow for monitoring the movement of messenger RNA.

Mar 21, 2016
Kerry Grens

WIKIMEDIA, ROBINSON RCRISPR—a bacterial immune response best known for its genome-editing applications in the lab—has yet again been adapted for scientific purposes, this time to track RNA within cells. Researchers modified various components of CRISPR so that they could snap on to a specified messenger RNA (mRNA) within the nucleus, then enter the cytoplasm as a complex, where its fluorescent signal could be tracked.

“This work . . . sets the foundation for manipulation of the transcriptome in addition to the genome by CRISPR/Cas9,” the authors wrote in their report, published in Cell last week (March 17).

The alterations included neutering the Cas9 enzyme—which ordinarily cuts DNA—so it would grab the RNA target without cleaving it, and sticking on a fluorescent protein to allow for visual tracking. A guide RNA, along with the addition of an oligonucleotide sequence, sent the Cas9 RNA-ward.

“Just as CRISPR-Cas9 is making genetic engineering accessible to any scientist with access to basic equipment, RNA-targeted Cas9 may support countless other efforts for studying the role of RNA processing in disease or for identifying drugs that reverse defects in RNA processing,” study coauthor David Nelles of the University of California, San Diego, said in a press release.

Editor’s note (March 21): Readers who commented on The Scientist’s Facebook page rightly pointed out that the DNA helix pictured above is backwards.